CVE-2018-21099 in R7800
Summary
by MITRE
NETGEAR R7800 devices before 1.0.2.60 are affected by command injection by an authenticated user.
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Analysis
by VulDB Data Team • 06/03/2024
The vulnerability CVE-2018-21099 represents a critical command injection flaw in NETGEAR R7800 wireless routers running firmware versions prior to 1.0.2.60. This issue arises from insufficient input validation within the device's web interface, specifically affecting the system command execution functionality. The vulnerability allows an authenticated attacker with access to the router's administrative interface to inject arbitrary commands that are subsequently executed with elevated privileges. The flaw exists in the parameter handling mechanisms used by the router's web server component, which fails to properly sanitize user-supplied input before incorporating it into system commands. This type of vulnerability falls under CWE-77 which categorizes improper neutralization of special elements used in commands, and directly aligns with ATT&CK technique T1059.001 for command and script injection.
The operational impact of this vulnerability is severe as it provides attackers who have gained administrative credentials with the ability to execute arbitrary code on the affected device. This command injection capability enables attackers to perform a wide range of malicious activities including but not limited to modifying router configurations, establishing persistent backdoors, accessing network traffic, redirecting DNS requests, or even using the compromised device as a pivot point for further attacks within the local network. The authenticated nature of the vulnerability means that an attacker must first obtain valid administrative credentials, but this is often achievable through credential brute force attacks, default credential exploitation, or social engineering techniques that are commonly successful against consumer-grade networking equipment. The affected R7800 devices are widely deployed in residential and small office environments, making them attractive targets for attackers seeking to establish persistent access to networks.
Mitigation strategies for CVE-2018-21099 primarily focus on firmware updates and network segmentation. The most effective immediate solution is to upgrade the router's firmware to version 1.0.2.60 or later, which includes proper input validation and sanitization mechanisms that prevent command injection attacks. Network administrators should also implement strict access controls by changing default administrative passwords to strong, unique credentials and disabling unnecessary services such as remote management or telnet access. Additional protective measures include implementing network monitoring to detect unusual command execution patterns, restricting administrative access to trusted IP addresses only, and regularly auditing router configurations for unauthorized changes. The vulnerability highlights the importance of secure coding practices in embedded systems and demonstrates how authentication bypasses or credential compromise can lead to privilege escalation through command injection flaws. Organizations should also consider implementing network access controls and segmentation to limit the potential damage from compromised devices, as the command injection vulnerability could enable attackers to use the router as a launchpad for broader network infiltration activities.